CN112550209B

CN112550209B - Active hood apparatus

Info

Publication number: CN112550209B
Application number: CN202011504079.3A
Authority: CN
Inventors: 邓强; 周澄靖; 陈虹吉
Original assignee: Dongfeng Motor Co Ltd
Current assignee: Dongfeng Motor Co Ltd
Priority date: 2020-12-17
Filing date: 2020-12-17
Publication date: 2022-04-26
Anticipated expiration: 2040-12-17
Also published as: CN112550209A

Abstract

The invention discloses an active engine cover device, which comprises a controller, a jacking device and an engine cover, wherein the front end of the engine cover is provided with a rotating unit, and the rear end of the engine cover is provided with a jacking unit; the controller controls the jacking device to actuate according to the collision signal, the jacking device drives the jacking unit to jack, the jacking unit drives the rear end of the engine cover to jack, the front end of the engine cover rotates through the rotating unit, the jacking unit comprises a first jacking piece, a second jacking piece and a switching assembly, and the switching assembly is connected between the first jacking piece and the second jacking piece; when the engine cover is jacked, the first jacking piece and the second jacking piece are fixedly connected through the switching assembly; after jacking of the engine cover and when the engine cover is collided, the switching component unlocks the first jacking piece and the second jacking piece, so that the first jacking piece and the second jacking piece can rotate relatively, and the rear end of the engine cover descends. In the invention, when the body part of the pedestrian impacts the engine hood to generate secondary collision, the switching component drives the engine hood to absorb energy and reduce the energy, thereby reducing the damage to the head of the human body and improving the safety performance.

Description

Active hood apparatus

Technical Field

The invention relates to the technical field of automobiles, in particular to an active engine hood device.

Background

With the official release of CNCAP2021, the requirements for pedestrian protection are continuously tightened. After the passenger car collides with a pedestrian, the active engine hood device can be actively lifted, the gap between the engine hood and the engine room is increased, the secondary collision between the head of the pedestrian and a hard object in the engine room is avoided, and the injury to the head of the pedestrian is reduced. The existing active hood device has the following problems in structure:

1. after the active engine hood is actuated, due to the fact that no crushing structure exists, a hinge of the engine hood and an actuator form a new rigid body, the head of a pedestrian impacts nearby the area, secondary collision can be caused, and injury to the head of the pedestrian is increased;

2. the active engine hood hinge adopts a five-connecting-rod hinge structure, has redundant structural components, and has the problems of large material consumption and high cost;

3. when the active engine cover is actuated, the front part cannot be lifted normally, and the safety clearance between the engine cover and hard objects in a cabin is reduced due to structural limitation.

Therefore, there is a need for an active hood device that is less harmful to the human body, highly safe, and low in cost.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide an active hood device which can reduce the damage to a human body, has high safety and low cost.

The technical scheme of the invention provides an active engine cover device which comprises a controller, a jacking device and an engine cover, wherein the front end of the engine cover is provided with a rotating unit, and the rear end of the engine cover is provided with a jacking unit; the controller controls the jacking device to actuate according to a collision signal, the jacking device drives the jacking unit to jack, the jacking unit drives the rear end of the engine cover to jack, the front end of the engine cover rotates through the rotating unit, the jacking unit comprises a first jacking piece, a second jacking piece and a switching assembly, and the switching assembly is connected between the first jacking piece and the second jacking piece;

when the engine cover is jacked, the first jacking piece and the second jacking piece are fixedly connected through a switching assembly;

and after the engine cover is jacked and collided, the switching component unlocks the first jacking piece and the second jacking piece, so that the first jacking piece and the second jacking piece can rotate relatively, and the rear end of the engine cover descends.

Further, the switching assembly comprises a first ratchet wheel, a first pawl, a second pawl and a crushing piece, wherein the first pawl is matched with the first ratchet wheel, and the second pawl is matched with the crushing piece;

when the engine cover is lifted, the first pawl is immovable relative to the first ratchet wheel, and the second pawl is immovable relative to the crushing piece;

after the engine cover is lifted and collided, the first pawl rotates relative to the first ratchet wheel, and the second pawl cuts the crushing piece.

Further, the crushing piece is a crushing wheel, the crushing wheel comprises a fixing part and a crushing edge, the crushing edge is located on the outer edge of the fixing part, the fixing part is coaxially and fixedly connected with the first ratchet wheel, and the crushing edge is matched with the second pawl.

Furthermore, first jacking piece with through first pivot rotatable coupling between the second jacking piece, first ratchet with crushing piece with first pivot fixed connection, first jacking piece is close to jacking ware one side, the second jacking piece is close to bonnet one side, first pawl with the second pawl respectively fixed connection be in on the relative both sides face of second jacking piece.

Further, the second pawl is a knife-type pawl.

Furthermore, the switching assembly comprises a second rotating shaft, a rotating disc, a torsional spring, a blocking block and a blocking pin, the first jacking piece and the second jacking piece are rotatably connected through the second rotating shaft, the rotating disc is sleeved on the second rotating shaft, and the torsional spring is installed on the rotating disc;

when the engine cover is lifted, the blocking pin is inserted into the blocking block and used for limiting the rotation of the torsion spring;

after the engine cover is lifted and collided, the stop pin is broken, and the torsion spring is unlocked.

Furthermore, the first jacking piece is a first rotating rod, and the second jacking piece is a second rotating rod;

when the engine cover is lifted, the first rotating rod and the second rotating rod are kept on the same straight line;

after the engine cover is lifted and collided, the first rotating rod and the second rotating rod can rotate relatively.

Further, the lifting device comprises a first connecting rod and a second connecting rod, one end of the first connecting rod is connected with the lifting device, the other end of the first connecting rod is rotatably connected with the first rotating rod, the second rotating rod is rotatably connected with one end of the second connecting rod, and the other end of the second connecting rod is fixedly connected with the engine cover.

Further, a second ratchet wheel and a third pawl are arranged between the first connecting rod and the first rotating rod;

when the engine cover is lifted, the third pawl rotates relative to the second ratchet wheel;

after the engine cover is lifted and collided, the third pawl is fixed relative to the second ratchet wheel, and the first rotating rod is fixed.

Further, the rotation unit includes a front hook connected to a front end of the hood and capable of rotating in a fixing groove, and a fixing groove.

After adopting above-mentioned technical scheme, have following beneficial effect:

when the engine cover is jacked, the first jacking piece and the second jacking piece are fixedly connected through the switching assembly, and the first jacking piece and the second jacking piece can jointly drive the engine cover to jack; after jacking of the engine cover and when the engine cover is collided, the switching component unlocks the first jacking piece and the second jacking piece, so that the first jacking piece and the second jacking piece can rotate relatively, and the rear end of the engine cover descends. The secondary damage to the human body and the raised engine cover during secondary collision is avoided, and the safety performance is improved.

Drawings

The disclosure of the present invention will become more readily understood by reference to the drawings. It should be understood that: these drawings are for illustrative purposes only and are not intended to limit the scope of the present disclosure. In the figure:

FIG. 1 is a schematic view of an active hood assembly according to an embodiment of the present invention prior to hood lift-up;

FIG. 2 is a schematic view of an active hood apparatus during hood lift according to one embodiment of the present invention;

FIG. 3 is a schematic view of an active hood assembly prior to hood lifting in accordance with one embodiment of the present invention;

FIG. 4 is an enlarged view of a portion of the second ratchet before the hood is lifted according to one embodiment of the present invention;

FIG. 5 is an enlarged view of a portion of the first ratchet prior to the hood being raised in accordance with one embodiment of the present invention;

fig. 6 is an enlarged view of a portion of the crush member before hood lifting in accordance with one embodiment of the present invention;

FIG. 7 is a schematic view of an active hood apparatus during hood lift according to one embodiment of the present invention;

FIG. 8 is an enlarged view of a portion of the second ratchet during hood lifting in accordance with one embodiment of the present invention;

FIG. 9 is an enlarged view of a portion of the first ratchet during hood lifting in accordance with one embodiment of the present invention;

FIG. 10 is an enlarged view of a portion of the crush member during hood lifting in accordance with one embodiment of the present invention;

FIG. 11 is a schematic view of an active hood apparatus with a collapsed hood according to an embodiment of the present invention;

FIG. 12 is an enlarged view of a portion of a second ratchet wheel during collapse of the hood in accordance with one embodiment of the present invention;

FIG. 13 is an enlarged view of a portion of the first ratchet wheel during collapse of the hood in accordance with one embodiment of the present invention;

fig. 14 is an enlarged view of a portion of a crush member of a hood collapsing in accordance with an embodiment of the present invention;

FIG. 15 is an exploded view of an active hood device according to one embodiment of the present invention;

FIG. 16 is a schematic diagram of a switching assembly of the active hood device according to the second embodiment of the present invention;

fig. 17 is a partially exploded view of the switching assembly of the active hood device according to the second embodiment of the present invention.

Reference symbol comparison table:

a jack 1 and a hood 2;

the rotating unit 3: a front hook 31 and a fixing groove 32;

the jacking unit 4 comprises a third rotating shaft 40, a first jacking piece 41, a second jacking piece 42, a switching assembly 43, a first rotating shaft 44, a first connecting rod 45, a second connecting rod 46, a second ratchet wheel 47, a third pawl 48, a sliding rail 49, a first ratchet wheel 431, a first pawl 432, a second pawl 433, a crushing piece 434, a second rotating shaft 435, a rotating disc 436, a torsion spring 437, a blocking block 438, a blocking pin 439, a fixing part 4341, a crushing edge 4342, a protrusion 4361 and a groove 4351.

Detailed Description

The following further describes embodiments of the present invention with reference to the accompanying drawings.

It is easily understood that according to the technical solution of the present invention, those skilled in the art can substitute various structures and implementation manners without changing the spirit of the present invention. Therefore, the following detailed description and the accompanying drawings are merely illustrative of the technical aspects of the present invention, and should not be construed as limiting or restricting the technical aspects of the present invention.

The terms of orientation of up, down, left, right, front, back, top, bottom, and the like referred to or may be referred to in this specification are defined relative to the configuration shown in the drawings, and are relative terms, and thus may be changed correspondingly according to the position and the use state of the device. Therefore, these and other directional terms should not be construed as limiting terms.

In some embodiments of the present invention, as shown in fig. 1-2, the active hood apparatus includes a controller (not shown), a lifter 1 and a hood 2, wherein a rotation unit 3 is disposed at a front end of the hood 2, and a lifter unit 4 is disposed at a rear end of the hood 2; the controller controls the jacking device 1 to act according to the collision signal, the jacking device 1 drives the jacking unit 4 to jack, the jacking unit 4 drives the rear end of the engine cover 2 to jack, the front end of the engine cover 2 rotates through the rotating unit 3, the jacking unit 4 comprises a first jacking piece 41, a second jacking piece 42 and a switching assembly 43, and the switching assembly 43 is connected between the first jacking piece 41 and the second jacking piece 42;

when the engine cover 2 is lifted, the first lifting piece 41 and the second lifting piece 42 are fixedly connected through the switching component 43;

after the hood 2 is lifted and collided, the switching member 43 unlocks the first lifter 41 and the second lifter 42 to enable the first lifter and the second lifter to rotate relatively, and lowers the rear end of the hood 2.

Specifically, jacking ware 1 can be the telescopic link, and when the controller received vehicle collision signal, control jacking ware 1 stretched out, and jacking ware 1 drives first jacking piece 41 and second jacking piece 42 and rotates for first jacking piece 41 and second jacking piece 42 can drive the rear end jacking of bonnet 2, and the rear end of bonnet 2 upwards overturns around the rotation unit 3 of front end, increases the clearance between bonnet and cabin. The left side in fig. 1 is the "front end" and the right side is the "rear end".

When a human body collides secondarily against the hood 2, the direction of the secondary collision is as indicated by the hollow arrow in fig. 2. Especially, when the hinge area of the rear end of the bonnet 2 is exerted with downward overturning pressure by secondary collision, the pressure enables the switching component 43 to unlock the first jacking piece 41 and the second jacking piece 42, so that the first jacking piece 41 and the second jacking piece 42 can rotate relatively, and after the first jacking piece 41 and the second jacking piece 42 rotate relatively, the rear end of the bonnet 2 falls back downwards, so that the harm to a human body is reduced, and the safety performance is improved.

It will be appreciated by those skilled in the art that when the force of the secondary collision is large enough, the unlocking of the switching assembly 43 can also be achieved when a human body collides with the middle of the hood 2, so that the rear end of the hood 2 falls back downward for reducing the injury to the human body.

In some embodiments of the present invention, as shown in fig. 1-2, the first lifting member 41 is a first rotating rod, and the second lifting member 42 is a second rotating rod;

when the engine cover 2 is lifted, the first rotating rod and the second rotating rod are kept on the same straight line;

after the engine cover 2 is lifted and collided, the first rotating rod and the second rotating rod can rotate relatively.

Specifically, as shown in fig. 1-2, before the switching component 43 unlocks the first rotating rod and the second rotating rod, the first rotating rod and the second rotating rod are fixedly connected through the switching component 43 to form a straight rod.

As shown in fig. 2, when the jack 1 extends, the first rotating rod and the second rotating rod are driven to rotate counterclockwise, and the rear end of the engine cover 2 is jacked up.

As shown in fig. 11, when the hood 2 is lifted and collided, the switching member 43 unlocks the first lifter 41 and the second lifter 42 so that the relative rotation therebetween is possible. In fig. 11, the first lifting member 41 is not moved, the second lifting member 42 is rotated clockwise relative to the first lifting member 41, and the hood 2 is dropped.

Alternatively, the first lifter 41 may be rotated clockwise, and the second lifter 42 may be rotated counterclockwise, so that the switching assembly 43 is also moved downward and rearward, and the hood 2 is dropped.

Optionally, the first lifting member 41 and the second lifting member 42 may also be a curved rod, or a rotating member with a certain length such as a plate member, which can be driven by the lifting device 1 to push the hood 2 to lift.

Alternatively, before the engine cover 2 is collided, the first lifter 41 and the second lifter 42 are not necessarily on the same line, and a relatively fixed position is maintained.

In some embodiments of the present invention, as shown in fig. 1, the present invention further includes a first link 45 and a second link 46, one end of the first link 45 is connected to the lifter 1, the other end is rotatably connected to the first rotating rod, the second rotating rod is rotatably connected to one end of the second link 46, and the other end of the second link 46 is fixedly connected to the hood 2.

Specifically, when the jack 1 extends, the first connecting rod 45 is pushed to move along the sliding rail 49, the sliding rail 49 is arranged approximately along the front-back direction of the engine cover 2, when the first connecting rod 45 slides backwards, the first jacking piece 41 and the second jacking piece 42 are driven to rotate anticlockwise, the second jacking piece 42 pushes the second connecting rod 46 to move upwards, and the second connecting rod 46 pushes the rear end of the engine cover 2 to move upwards.

Alternatively, the first lifting member 41 and the second lifting member 42 can be driven to rotate or lift by other rods or transmission members.

For example: the first connecting rod 45 can be replaced by a sliding block, the sliding block slides back and forth along the sliding rail 49, and the jacking device 1 pushes the sliding block to move backwards.

Preferably, the jack 1 is not connected to the first link 45, and only when the jack 1 extends out, the jack contacts the first link 45; when the jack 1 is retracted, it is separated from the first link 45.

In some embodiments of the present invention, as shown in fig. 1 to 2, the rotating unit 3 includes a front hook 31 and a fixing groove 32, and the front hook 31 is coupled to a front end of the hood 2 and can rotate in the fixing groove 32.

The front hook 31 has a top end rotatably coupled to a front end of the hood 2 and a bottom end capable of rotating in the fixing groove 32. When the rear end of the hood 2 moves up and down, the front hook 31 rotates in the fixing groove 32.

Alternatively, the rotating unit 3 may be a hinge, or other structure such as a double link.

The first embodiment is as follows:

as shown in fig. 3-15, the switching assembly 43 includes a first ratchet 431, a first pawl 432, a second pawl 433, and a crush 434, the first pawl 432 cooperating with the first ratchet 431, the second pawl 433 cooperating with the crush 434;

when the hood 2 is lifted, the first pawl 432 is immovable with respect to the first ratchet 431 and the second pawl 433 is immovable with respect to the crushing member 434;

when the hood 2 is lifted and crashed, the first pawl 432 rotates relative to the first ratchet 431 and the second pawl 433 cuts the crush member 434.

3-6 are schematic diagrams before the engine cover 2 is lifted; FIGS. 7-10 are schematic views of the hood 2 when raised; fig. 11 to 14 are schematic views of the hood 2 when a secondary collision occurs.

Specifically, as shown in fig. 3, the first lifting member 41 is a first rotating rod, and the second lifting member 42 is a second rotating rod; before and during jacking of the engine cover 2, the first rotating rod and the second rotating rod are kept on the same straight line.

As shown in fig. 5, the first lifting member 41 and the second lifting member 42 are rotatably connected through a first rotating shaft 44, the first ratchet wheel 431 and the crushing member 434 are fixedly connected with the first rotating shaft 44, the first lifting member 41 is close to one side of the lifting device 1, the second lifting member 42 is close to one side of the engine cover 2, and the first pawl 432 and the second pawl 433 are respectively and fixedly connected to two opposite sides of the second lifting member 42.

As shown in fig. 15, the first rotating shaft 44 passes through the first ratchet wheel 431, the second lifting member 42, the first lifting member 41 and the crushing member 434 in sequence, the first pawl 432 is installed on one side surface of the second lifting member 42 where the first ratchet wheel 431 is installed and is engaged with the first ratchet wheel 431, and the second pawl 433 is installed on the other side surface of the second lifting member 42 and is engaged with the crushing member 434.

As shown in fig. 5, before the hood 2 is lifted, the first ratchet 431 interferes with the first pawl 432.

As shown in fig. 9, when the hood 2 is lifted, the first lifting member 41 rotates counterclockwise, which drives the first ratchet 431 to move upward, the first pawl 432 and the first ratchet 431 remain stationary, and the second lifting member 42 and the first lifting member 41 remain stationary.

As shown in fig. 6, before the hood 2 is lifted, the second pawl 433 interferes with the crushing member 434;

as shown in fig. 9, when the hood 2 is lifted, the second pawls 433 remain stationary with respect to the crushing members 434.

When the hood 2 is impacted for the second time, the second lifting rod 42 is forced to rotate clockwise, and the second pawl 433 starts to cut the crushing member 434.

As shown in fig. 13 to 14, after the crushing member 434 is cut, the second lifting member 42 rotates clockwise and downward, so that the first pawl 432 rotates clockwise along the first ratchet 431, and the second lifting member 42 drives the rear end of the hood 2 to fall back downward.

In the embodiment, when the automobile collides for the first time, the controller controls the engine cover 2 to be turned upwards and opened; when a human body collides with the hood 2 for a second time, the crushing member 434 is crushed, and the hood 2 falls back, so that the injury to the human body is reduced, and the safety performance is improved.

Further, as shown in fig. 14, the crushing member 434 is a crushing wheel, the crushing wheel includes a fixed portion 4341 and a crushing edge 4342, the crushing edge 4342 is located at an outer edge of the fixed portion 4341, the fixed portion 4341 is coaxially and fixedly connected with the first ratchet 432, and the crushing edge 4342 is engaged with the second pawl 433.

The crushing edge 4342 may be partially disposed at an edge of the fixing portion 4341. The crushing edge 4342 has a small thickness and a low strength, and is easily crushed or cut by the second pawl 433.

When jacking, the first jacking piece 41 and the second jacking piece 42 are kept still mainly through the action between the first ratchet wheel 431 and the first pawl 432;

when the hood 2 is collided, the collision force applies a reverse force to the second lifter 42, and the first pawl 432 is relatively movable or rotatable with respect to the first ratchet 431. The second pawl 433 crushes the crushing edge 4342 quickly under the impact force, and the hood 2 falls quickly.

Preferably, the second pawl 433 is a knife-type pawl to facilitate cutting of the crushed edge 4342.

Further, as shown in fig. 15, the lifting device further comprises a first connecting rod 45 and a second connecting rod 46, one end of the first connecting rod 45 is connected with the lifting device 1, the other end of the first connecting rod 45 is rotatably connected with the first lifting piece 41, the second lifting piece 42 is rotatably connected with one end of the second connecting rod 46, and the other end of the second connecting rod 46 is fixedly connected with the engine cover 2. A second ratchet wheel 47 and a third pawl 48 are arranged between the first connecting rod 45 and the first jacking piece 41;

when the hood 2 is lifted, the third pawl 48 rotates relative to the second ratchet 47;

when the hood 2 is lifted and crashed, the third pawl 48 is not moved relative to the second ratchet 47, and the first rotating lever is not moved.

Specifically, the second ratchet wheel 47 is fixedly connected with the first link 45 through the third rotating shaft 40, and the third pawl 48 is fixedly connected to the first lifting member 41.

As shown in fig. 4, before the hood 2 is lifted up, the third pawl 48 interferes with the second ratchet 47.

As shown in fig. 8, when the hood 2 is lifted, the first lifter 41 rotates counterclockwise and drives the third pawl 48 to move upward, and the third pawl 48 rotates relative to the second ratchet wheel 47.

As shown in fig. 12, when the hood 2 is impacted for the second time, the third pawl 48 is caught on the second ratchet wheel 47, so that the first lifting member 41 is not moved at this time, and the second lifting member 42 is rotated clockwise by the impact force.

The third pawl 48 cooperates with the second ratchet wheel 47 to prevent the first lifter 41 from being reversed when the hood 2 is lifted; when the bonnet 2 receives secondary collision, make first jacking piece 41 motionless, be favorable to the clockwise rotation of second jacking piece 42, avoid because first jacking piece 41 rotates with second jacking piece 42 simultaneously, the card is dead between the two.

In this embodiment, receive secondary collision through the conquassation piece when being conquassated, drive falling back downwards of bonnet, reduce the injury to human head. In this embodiment, the first jacking piece and the second jacking piece are simple in structure and low in cost.

Example two:

as shown in fig. 16-17, the switching assembly 43 includes a second rotating shaft 435, a rotating disc 436, a torsion spring 437, a blocking block 438 and a blocking pin 439, the first lifting member 41 and the second lifting member 42 are rotatably connected through the second rotating shaft 435, the rotating disc 436 is sleeved on the second rotating shaft 435, and the torsion spring 437 is mounted on the rotating disc 436;

when the hood 2 is lifted, the stopper pin 439 is inserted into the stopper 438 to restrict the rotation of the torsion spring 437;

when the hood 2 is lifted and collided, the stopper pin 439 is broken to unlock the torsion spring 437.

Specifically, two protrusions 4361 are disposed on the rotary disc 436, and the protrusions 4361 are inserted into the grooves 4351 of the second rotating shaft 435, so that the second rotating shaft 435 is fixedly connected to the rotary disc 436.

The clamp spring 437 is sleeved on the rotating disc 436, one end of the clamp spring 437 is abutted to or fixedly connected with the rotating disc 436, and the other end is abutted to or fixedly connected with the second jacking piece 42.

A stopper 438 is installed on one end of the snap spring 437, and a stopper pin 439 is installed on the other end of the snap spring 437.

In a normal state of the hood 2, the blocking pin 439 is inserted into the blocking piece 438 to limit the rotation of the torsion spring 437, and the rotation of the rotary disk 436 and the second rotating shaft 435 is limited, so that the relative rotation between the second lifting member 42 and the first lifting member 41 is prevented.

When the engine cover 2 is subjected to a secondary collision, the second jacking member 42 tends to rotate clockwise, so that the other end of the clamp spring 437 is driven to apply pressure to the blocking pin 439 until the blocking pin 439 is crushed, the blocking pin 439 is separated from the blocking block 438, the torsion spring 437 rotates under the action of the second jacking member 42, and the torsion spring 437 absorbs the collision force and drives the rotating disc 436 and the second rotating shaft 435 to rotate.

In this embodiment, through stopping that the round pin is crushd when receiving secondary collision, drive the downward fall back of bonnet, reduce the injury to human head.

The foregoing is considered as illustrative only of the principles and preferred embodiments of the invention. It should be noted that, for those skilled in the art, several other modifications can be made on the basis of the principle of the present invention, and the protection scope of the present invention should be regarded.

Claims

1. An active engine cover device comprises a controller, a jacking device (1) and an engine cover (2), wherein the front end of the engine cover (2) is provided with a rotating unit (3), and the rear end of the engine cover is provided with a jacking unit (4); the controller controls the jacking device (1) to actuate according to a collision signal, the jacking device (1) drives the jacking unit (4) to jack, the jacking unit (4) drives the rear end of the engine cover (2) to jack, the front end of the engine cover (2) rotates through the rotating unit (3), the device is characterized in that the jacking unit (4) comprises a first jacking piece (41), a second jacking piece (42) and a switching component (43), the switching component (43) is connected between the first jacking piece (41) and the second jacking piece (42),

the lifting device is characterized by further comprising a first connecting rod (45) and a second connecting rod (46), wherein one end of the first connecting rod (45) is connected with the lifting device (1), the other end of the first connecting rod (45) is rotatably connected with the first lifting piece (41), the second lifting piece (42) is rotatably connected with one end of the second connecting rod (46), and the other end of the second connecting rod (46) is fixedly connected with the engine cover (2); when the engine cover (2) is jacked before jacking and after first collision, the first jacking piece (41) is fixedly connected with the second jacking piece (42) through a switching component (43);

after the engine cover (2) is jacked up and is collided for the second time, the switching component (43) unlocks the first jacking piece (41) and the second jacking piece (42), so that the first jacking piece and the second jacking piece can rotate relatively, and the rear end of the engine cover (2) descends.

2. The active hood device according to claim 1, wherein the switching assembly (43) comprises a first ratchet (431), a first pawl (432), a second pawl (433) and a crush member (434), the first pawl (432) cooperating with the first ratchet (431) and the second pawl (433) cooperating with the crush member (434);

when the engine cover (2) is lifted, the first pawl (432) is immovable relative to the first ratchet wheel (431), and the second pawl (433) is immovable relative to the crushing piece (434);

when the engine cover (2) is jacked up and collided, the first pawl (432) rotates relative to the first ratchet wheel (431), and the second pawl (433) cuts the crushing piece (434).

3. The active hood device according to claim 2, wherein the crushing member (434) is a crushing wheel, the crushing wheel comprises a fixed portion (4341) and a crushing edge (4342), the crushing edge (4342) is located at the outer edge of the fixed portion (4341), the fixed portion (4341) is coaxially and fixedly connected with the first ratchet (431), and the crushing edge (4342) is engaged with the second pawl (433).

4. The active hood device according to claim 2, wherein the first lifter (41) and the second lifter (42) are rotatably connected by a first rotating shaft (44), the first ratchet wheel (431) and the crushing member (434) are fixedly connected with the first rotating shaft (44), the first lifter (41) is close to one side of the lifter (1), the second lifter (42) is close to one side of the hood (2), and the first pawl (432) and the second pawl (433) are respectively fixedly connected with two opposite sides of the second lifter (42).

5. The active hood device according to claim 2, wherein the second pawl (433) is a knife-type pawl.

6. The active hood device according to claim 1, wherein the switching assembly (43) comprises a second rotating shaft (435), a rotating disc (436), a torsion spring (437), a blocking block (438) and a blocking pin (439), the first lifting member (41) and the second lifting member (42) are rotatably connected through the second rotating shaft (435), the rotating disc (436) is sleeved on the second rotating shaft (435), and the torsion spring (437) is mounted on the rotating disc (436);

when the engine cover (2) is lifted, the blocking pin (439) is inserted into the blocking block (438) for limiting the rotation of the torsion spring (437);

after the engine cover (2) is lifted and collided, the blocking pin (439) is broken to unlock the torsion spring (437).

7. The active hood device according to claim 1, wherein the first lifter (41) is a first rotating rod and the second lifter (42) is a second rotating rod;

when the engine cover (2) is lifted, the first rotating rod and the second rotating rod are kept on the same straight line;

after the engine cover (2) is lifted and collided, the first rotating rod and the second rotating rod can rotate relatively.

8. Active hood device according to claim 7, characterized in that a second ratchet (47) and a third pawl (48) are provided between the first link (45) and the first lever;

when the engine cover (2) is lifted, the third pawl (48) rotates relative to the second ratchet wheel (47);

when the engine cover (2) is lifted and collided, the third pawl (48) does not move relative to the second ratchet wheel (47), and the first rotating rod does not move.

9. Active hood device according to any of claims 1 to 8, characterized in that the turning unit (3) comprises a front hook (31) and a fixation groove (32), the front hook (31) being connected to the front end of the hood (2) and being able to turn in the fixation groove (32).